'Grey's Anatomy': The 10 Biggest Reveals From the Midseason Premiere

April makes her choice, Callie and Arizona make a big investment, Grey Sloan Memorial makes a big change and seven other highlights.

[Warning: This story contains spoilers from the "Take It Back" episode of ABC's Grey's Anatomy.]

ABC's Grey's Anatomy returned from its midseason hiatus Thursday with a modest time jump and fully loaded episode that set the table for the remainder of its 10th season.

During the hour, April made her choice between Jackson and Matthew (more on that here in our interview with Sarah Drew), Callie (Sara Ramirez) and Arizona (Jessica Capshaw) made a big investment and Grey Sloan Memorial is making a major change (or at least trying to). Here are the 10 big reveals from the episode.

1. April makes her choice -- and it's Jackson (Jesse Williams). They eloped to Reno and are keeping their relationship a secret from everyone. (Check out our postmortem interview with Drew here.)

2. Shane (Gaius Charles) is back at the hospital but Owen (Kevin McKidd) is going to make his life impossible -- at least to start -- after the latter learns of the newbie's sexcapades with Cristina (Sandra Oh).

3. Alex's (Justin Chambers) father, Jimmy, dies. But not before Alex can give him a happy send-off after lying to him about how his remaining family feels about him. As part of Alex's frustration over his lost time with his father, he beats the crap out of Shane for botching the surgery.

4. Callie and Arizona are back in the saddle! After a tearful Arizona revealed that their apartment -- filled with memories of her amputation and subsequent recovery -- didn't feel like her home, the couple buy a fixer-upper and move into a new house in a bid to start over.

5. Ben (Jason George) joins the residents' gang and reveals that he originally left his L.A.-based program because he wanted to spend more time with Bailey (Chandra Wilson), who accused him of causing her OCD.

6. Stephanie (Jerrika Hinton) is still in shock after Jackson ditched her for April at the wedding. She tearfully confesses she knew better to Leah (Tessa Ferrer), who accuses Jackson of taking advantage of the situation considering he is their boss. (Leah accuses Arizona of doing the same with her, ditto for Cristina with Shane.) The still-scorned Leah suggests they do something about it.

7. Speaking of Leah and Stephanie, the residents file claims with HR that prompt the hospital to strongly consider a zero-tolerance policy when it comes to relationships with subordinates. Pre-existing married couples -- Meredith and Derek, Arizona and Callie, Bailey and Ben -- naturally are excluded. Naturally, this will put pressure on Jackson and April to reveal their marriage and Alex and Jo to figure out what their future together is.

8. Alex and Jo (Camilla Luddington) continue their bumpy relationship, with Alex now referring to his partner as his "fiancée" -- much to Jo's surprise. Their slow-mance continues to be one of Grey's Anatomy's most promising stories this season as Alex slowly but surely opens up to reveal his big but damaged beating heart.

9. Cristina and Meredith (Ellen Pompeo) are back! The duo has overcome -- at least temporarily -- their family vs. career debate.

10. Meredith and Derek (Patrick Dempsey) are at odds over his White House gig. Mer is angry that this was supposed to be her time to focus on career after making professional sacrifices for their family. Derek, meanwhile, is being vetted by the White House, who uncover a $3,500 monthly payment he makes to the family of a former high school hockey teammate whose life permanently changed after he suffered a brain bleed Derek caused.

What were your highlights? Which story line are you most looking forward to seeing play out in the remainder of season 10? Hit the comments below with your thoughts. Grey's Anatomy airs Thursdays at 9 p.m. on ABC.